Centralized traffic controlling system for railroads



March 21, 1944 i 'r. 'J'. JUDGE CENTRALIZED TRAFFIC CONTROLLINGw SYSTEM FOR RAILRQADS Filed July 9, 1941 Patented Mar. 21, 1944 CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS Thomas J. Judge, Rochester, N. Y., assignor to General Railway Signal Company, Rochester,

Application July 9, 1941, Serial No. 401,608

14 Claims.

The present invention relates to centralized traffic controlling systems of the unit-wire type, and more particularly to an arrangement of circuits and devices for controlling signals at a distant location over a single line circuit and indicating the condition of occupancy of a track circuit adjacent said signals over said line circuit irrespective of whether a signal was at that time held clear or was then held at stop due to the removal of energy from said line circuit at the control point.

The usual way of controlling signals at a distant point over a line circuit is by the application of current of one or another character to a line circuit depending on the particular signal to be cleared and to leave the line circuit deenergized when all the signals are to be held at stop, and in order to apply such current one or more sources of current at the control point are employed. Although it would be possible to indicate the condition of occupancy of a track circuit over the signal control circuit by opening such signal control circuit, this would only be useful if signal control energy were at all times applied to the line circuit to hold a signal at clear. There are, however, times when no such energy is applied at the control point to such line circuit, this by reason of the fact that at times it is desirable to hold all the signals at stop. In view of these facts it is proposed in accordance with the present invention to indicate the condition of occupancy of a track circuit while signal control energy is applied to the line circuit from the control point by changing the extent of flow of such current, and it is further proposed, to indicate the condition of occupancy of the track circuit when no signal energy is applied at the control point by the application of energy to the line circuit at the signal location. It is further proposed in accordance with the present invention to provide means whereby no energy can be applied to either end of the line circuit if energy has already been applied to the other end of the line circuit.

Other objects, purposes, and characteristic features of the present invention will in part be described in the specification hereinafter and will in part be obvious from the accompanying drawing which illustrates one form the present invention may take.

Structure Referring to the drawing, the right-hand portion of this drawing illustrates the apparatusat a field location, whereas the apparatus shown at the left-hand of the drawing illustrates the apparatus that is located in the central office. At the field station is shown a section of main track having rails ill to which the rails H of a 'side' track are connected by a track switch SW, in-

sulating joints if! having been employed to segremain track and into the siding, respectively These signals 2A, 23, IA and IB are governed by a signal control relay SG and by switch box contacts reflecting the position of the track switch SW. This signal control relay SG is a relay of the polar neutral type having neutral contacts i5, i5 and i1 and having a polar contact l8.- Adjacent this signal control relay SG has been illustrated a signal control repeater relay SGP which is at times controlled through the front contacts ii of the signal control relay SG. This signal control repeater relay SGP is, however, not used for controlling the signals and is merely called a signal control repeater relay because it is picked up through a front contact of the signal control relay SG.

In the central office is provided a miniature track layout MT provided with a signal control lever SGL and a track indicating lamp or indicator IK. As shown this indicator lamp IK. may

be energized through either one of two circuits,

one including the front contact 20 of the track indicator relay 'IKA and the other including a front contact 2! of the track indicator reIay'TKB. It is thus seen that the lamp IK will be illuminated if either one of the two track. indicator relays TKAv or TKB assume its energizedposition. In the central office is located a line battery B, the mid-point of which is connected to a common return wire C. At the field station there is also provided a source of current, the terminals of which have been designated plus and In order to ascertain the purpose and function of the devices briefly described it is deemed desirable to discuss the manner in which the system operates and the functions that it performs.

Operation The apparatus is shown in its normal signalsat-stopcondition. Under this condition of the apparatus the signal control lever SGL assumes its middle or neutral position, this lever [being moved to the right when an east-bound signal is to be cleared, and being moved to the left when a west-bound signal is to be cleared. With the signal lever SGL in its middle position no current can flow to the signal control rel-ay SG, and this signal control relay SG will assume its deenergized position.

Let us now assume that with lever SGL assuming its middle position and for one reason or another a train approaching the switch inadvertently passes a few feet beyond a signal all the signals being at stop as shown, and in so doing this train shunts and deenergizes the track relay T. This will, of course, cause dropping of the track relay T as a result of which the following energizing circuit for the track indicating relay TKB is closed: beginning at the terminal plus of the battery at the field station, back contact l6 of signal control relay SG, back contact I9 of signal. control repeater relay SGP, back contact 22 of the track relay T, line wire 25, contact 26 of the signal lever SGL closed when this signal lever assumes its middle position, winding of the track indicating relay TKB, common return wire and back to the other terminal minus of the field battery. The completion of this circuit will cause the track indicating relay TKB to assume its energized position, in which position its front or stick contact 27 is closed. The closure of this stick contact 2'! results in the shunting of the lever contact 26 so that movement of the signal lever SGL thereafter cannot result in either the deenergization of the indication relay TKB or the application of electrical energy to the line wire 25 from the central olifice end. The picking up of the track indicating relay TKB, of course, results in the closure of its front contact 2 l and the illumination of the track indicator lamp IK. It is thus seen that if the lever SGL assumes its middle position and energy is applied to the line circuit at the field location it results in the picking up of the indication relay TKB and in the opening of the signal control circuit at the back contact 21 of relay TKB in the central office. If now the train under consideration backs up to an extent to allow reenergization of the track relay T, the back contact 22 of this track relay T opens and interrupts the energizing circuit for the track indicator relay TKB and this relay TKB returns to its normal deenergized position.

Let us now assume that the train under consideration was, an east-bound train and occupied the main track adjacent the passing siding. Let us also assume that the operator intends to allow this train to proceed into the single track stretch and in order to do-so moves the signal control cating relay TKA, the back contact 21 of the track indicating relay TKB, line wire 25, front contact 22 of the track relay T, the winding of the signal control relay SG, and back to the common return wire C connected to the mid-point of the office battery B. The closure of the circuit just traced will cause the signal control relay to assume its right-hand energized position in which its polar contact I8 is to the right, its front contacts [5 and I! are closed, and its back contact 16 is open. If the track switch SW now assumes the main track position, as will for convenience be assumed, the signal 2A is cleared by the flow of current in the following circuit: beginning at the terminal plus of the field source of current, front contact "24 of the track relay T, front contact l5 of the signal control relay SG, polar contact I8 of this same relay assuming its right-hand position, mechanism of the signal 2A, and switch box contact 28 assuming its normal position and then through contacts controlled in accordance with traffic conditions ahead (not shown) and back to the other terminal of the same source. This will, of course result in clearing of the signal 2A.

Let us now assume that the train under consideration accepts the clear signal 2A and in so doing treads upon the detector track circuit resulting in the deenergization of the track relay T. This dropping of the track relay T by the opening of its front contact 24 causes the signal 2A to assume its stop condition and by the dropping of its contact 22 establishes a pick-up circuit for the signal control repeater relay SGP through a branch circuit which includes this back contact 22 of track relay T, front contact I! of signal control relay SG, the winding of the relay SGP, and the resistance R included in series therewith. The resistance R. may be an adjustable one and if employed enables the current value through relays TKA and SGP to be properly selected. The completion of this branch circuit by reason of its lower resistance, relay SG being a high resistance relay, causes an excess of current to flow in the line wire 25 which is suflicient to pick up the indicating relay TKA, which relay did not pick up in response to the current which flowed therethrough when the signal control relay SG was energized in series therewith. Of course, the batteries or direct current sources can be replaced by alternating current sources, and if so, it is the impedance, rather than the resistance of the circuits that controls the picking up of relay TKA. In other words, the dropping of the track relay 22 at a time when the signal control relay SG is energized results in the closure of a pick-up circuit for the relay SGP, and also results in the fiow of sufficient current through the track indicator relay TKA to pick it up. As soon as this relay SGP has been picked up it is stuck up through a stick circuit including the stick contact l9, which contact shunts around the front contact l! of the signal control relay SG, so that dropping of the signal control relay SG and the opening of its contact I1, due to opening of front contact 22 of track relay T, will not result in deenergization of the relay SGP. Signal control relay SG is sufficiently slow dropping (illustrated conventionally) to allow the stick circuit through front contact [9 of relay SGP to be completed before contact H of signal control relay SG opens. With the track indicator relay TKA now assuming its energized position due to current flowing through the signal control repeater relay SGP the indicating 'lamp IK is energized through the front contact Let us now assume that the operator in response to the illumination of the indicating lamp IK (relay TKAenergized),which manifests to him that the train has accepted the starting signal 2A and that he no longer has control over this signal returns the lever SGL to its middle position, This return of the signal control lever SGLto itsmi-ddle position will, of course, result in the deenergization of the track indicating relay 'IKA and the deenergization of the signal repeater relay SGP. As soon as the relay SGP drops current may flow through the Winding of the indicating relay TKB through the circuit including the contact 26 of the signal control lever SGL and the back contacts l6, l9 and 22 of the relay SG, SGP and T through the same circuit as heretofore traced. Picking up of the track indicator relay TKB will, of course, result in the illumination of the indicating lamp IK and by reason of the slow dropping characteristics of relay TKAthis will take place before the indicator relay 'I'KA has assumed its deenergized position so that a'continuous indication of occupancy of the track circuit containing track relay T is manifested by the indicating lamp IK. Relay TKB is now energized independently of the lever SGLthrough its stick contact 21 and with back contact 21 open the office battery B cannot be connected to line wire 25 by lever SGL.

The applicant has thus provided a unit wire signal control and track indication circuit in which a plurality of signals may be controlled and the occupancy of a track circuit associated with such signals indicated over the same line circuit, and in which although sources of current are employed at both ends of the line circuit provision is made whereby these sources of current may not be simultaneously applied to such line circuit and in which indication of a track circuit may be given irrespective of whether the line circuit is at that time energized to clear a signal or is at that time deenergized to hold such signal at stop. Having shown and described only one particular embodiment of the invention it is desired to be understood that the particular embodiment illustrated has been selected for the purpose of showing and to facilitate describing the underlying principles of the invention and apparatus that may be embodied therein to perform the functions of the invention, and that the particular embodiment selected does not exhaust all arrangements that may be employed to carry out the invention and that various. additions, changes, and modifications, maybe made to adapt the invention to the particular problem encountered in practicing the invention without departing from the spirit or scope of the invention. except as demanded by the scope of the following claims.

What I claim as new is:

1. In combination with a distant traffic controlling device. and a local control lever for con-- trolling the same; a track circuit including a track relay adjacent saidtraffic controli ing device; a control relay for controlling said traflic controlling device; indicator adjacent said lever for indicating the condition of occupancy of said track circuit; a first indicator relay and a second indicator relay for controlling said indicator; a line Wire extending from a local point at which said lever is located to said distant point where said control relay is located; two indication circuits one including said line wire, a contact of saidleverclosed when said lever is in actuated position, a local source of current, said first indicator relay, a front contact of said track relay and said control relay, and the other including said line wire, a contact closed when said lever assumes its normal position, said second indicator relay, a back contact of said track relay, a back contact of said control relay and a source or" current located at said distant point; and two circuits for controlling said indicator, one controlled by said first indicator relay and the other controlled by said second indicator relay.

2. In combination with a distant trafiic controlling device and a local control lever for controlling the same; a track circuit including a track relay adjacent said traific controlling device; a control relay for controlling said traffic controlling device; an indicator adjacent said lever for indicating the condition of occupancy of said track circuit; a first indicator relay and a second indicator relay for controlling said indicator; a line wire extending from a local point at which said lever is located to said distant point where said control relay is located; a control repeater relay adjacent said control relay controlled through a front contact of said control relay; two circuits, one including said line wire, a source of current at said control lever, contacts of said control lever closed when said lever assumes its active position, the winding of said first indicator relay and said control relay, and the other including said line wire, the winding of said second indicator relay, a contact closed When said lever assumes an inactive position, a back contact of said control repeater relay, a back contact of said control relay and a source of current adjacent said control relay; and two circuits for controlling said indicator, one including a contact controlled by said first indicator relay and the other including a contact controlled by said second indicator relay.

3. In combination with a local ofiice and a distant traflic controlling device; a track circuit including a track relay associated with said traffic controlling device; a control relay for controlling said trafiic controlling device; a line wire connecting said office and traffic controlling device; an indicator means at said office; a control lever at said office having an active position and an inactive position; a control repeater relay adjacent said trafiic controlling device; and two circuits one including a source of current at said office, contacts of said control lever closed when said lever is in its active position, said indicator means, said line wire, a front contact of said track relay, and said control relay, in series, and the other including said source of current, a contact of said control lever closed when it assumes its active position, said indicator means, said line wire, a back contact of said track relay, a front contact of said control relay, and the winding of said control repeater relay, in series.

4. In combination with a local office and a distant traffic controlling device; a track circuit including a track relay associated with said traffic controlling device; a control relay for controlling said traffic controlling device; a line wire connecting said office and trailic controlling device; an indicator means at said oilice; a control lever at said oflice having an active position and an inactive position; a control repeater relay adjacent said trafiic controlling device; two circuits one including a source of current at said ofiice, contacts of said control lever closed when said lever is in its active position, awinding of said indicator means, said line wire a front contact of said track relay and said control relay in series, and the other including said source of current, a contact of said control lever closed when it assumes its active position, a winding of said indicator means, said line wire, a back contact of said track relay, a front contact of said control repeater relay and its winding in series; and a third circuit including a contact of said control lever closed when said control lever assumes its inactive position, a winding of said indicator means, back contacts of said track relay, said control relay, and said control repeater relay, and a source of current adjacent said trafiic controlling device.

5. In combination, a central office, a field station, and a pair of line wires connecting said central ofiice and field station; a control lever and an indication means at said oflice; a traffic controlling relay and an associated track relay at said field station; a control circuit for said trafiic controlling relay including a source of current at said office, a contact of said control lever closed only when said lever assumes an active position, contacts of said indication means closed when said indication means is in a deenergized condition, said pair of line Wires, a front contact of said track relay and the winding of said trafiic controlling relay; and two circuits for said indication means one including the winding of such indication means, a contact of said lever closed when said lever assumes an inactive position, said pair of line wires, a back contact of each of said track relay and said traffic controlling relay in series and a source of current at said field station, and the other including the winding of said indication means and a contact closed When said indication means is active in series, said pair of line wires and back contacts of said track relay and said trafiic controlling relay in series; whereby said lever cannot apply current to said pair of line wires so long as said indication means assumes its enersized and active condition.

6 In combination, a central ofiice, a field station and a pair of line wires connecting said central ofiice and field station; a control lever and a first and a second indication relay at said office; a traffic controlling relay and an associated track relay at said field station; a control circuit for said traffic controlling relay including a source of current at said ofiice, a contact of said control lever closed only when said lever assumes an actuated position, the winding of said first indication relay, a back contact of said second indication relay, said pair of line wires, a front contact of said track relay and the winding of said trafiic controlling relay; two circuits for said second indication relay one including the winding of such second indication relay, a contact of said lever closed when said lever assumes an inactive position, said pair of line wires, a back contact of each of said track relay and said traffic controlling relay in series and. a source of current at said field station, and the other including the winding and a front contact of said second indication relay in series, said ,pair of line wires and a back contact of each of said track relay and said traific controlling relay in series; and an indication circuit for said first indication relay including a contact of said lever closed when said lever assumes an active position, a back contact of said second indication relay, said pair of line wires, a back contact of said track relay and a front contact of said trafiic controlling relay.

7. In combination with a central office and a distant field station; a pair of line wires connecting said ofiice and station; a source of cur-- rent and a control lever at said oifice; a control relay and a control repeater relay at said field station; a track circuit including a track relay adjacent said control relay; a control circuit for said control relay including said source of current, contacts of said lever closed when said lever assumes an active position, said pair of line Wires, and a front contact of said track relay; a pick-up circuit for saidcontrol repeater relay including said contacts of said lever, said source of current, said pair of line wires, a back contact of said track relay and a front contact of said control relay; and a stick circuit for said control repeater relay including said contacts of said lever, said source of current, said pair of line wires, a back contact of said track relay and a front stick contact of said control repeater relay.

8. In combination with a central ofiice and a distant field station; a pair of line wires connecting said ofiice and station; a source of current, an indication means and a control lever at said office; a control relay and a control repeater relay at said field station; a track circuit including a track relay adjacent said control relay; a control circuit for said control relay including said source of current, said indication means, contacts of said lever closed when said lever assumes an active position, said pair of line wires, and a front contact of said track relay; a pick-up circuit for said control repeater relay including said contacts of said lever, said source of current, said indication means, said pair of line wires, a back contact of said track relay and a front contact of said control relay; and a stick circuit for said control repeater relay including said contacts of said lever, said source of current, said indication means, said pair of line wires, a back contact of said track relay and a front stick contact of said control repeater relay; the impedance of said relays and indication means being such that said indication means is rendered active when included in either said pick-up or said stick circuit but is not rendered active when included in series with said control circuit.

9. In combination with a central oifice and a distant field station; a pair of line wires connectingsaid office and station; a source of current, two indication means and a control lever at said ofiice; a control relay and a control repeater relay at said field station; a track circuit including a track relay adjacent said control relay; a control circuit for said control relay including said source of current, one of said indication means, contacts of said lever closed only when said lever assumes an active position, said pair of line wires, and a front contact of said track relay; a pick-up circuit for said control repeater relay including said contacts of said lever, said source of current, said one indication means, said pair of line Wires, a back contact of said track relay and a front contact of said control relay; a stick circuit for said control repeater relay including said contacts of said lever, said source of current, said one indication means, said pair of line wires, a back contact of said track relay and a front stick contact of said control repeater relay; the impedance of said relays and said one indication means being such that said one indication means is rendered active when included in either said pick-up or said stick circuit but is not rendered active when included in series with said control circuit; and another indication circuit including the other of said two indication means, contacts of said lever closed only when said lever assumes an inactive position, said pair of line wires, back contacts of said track relay and said control relay and a source of current at said field station;

10. In combination; a section of railway track, a track circuit for said section having a track relay; a signal for governing traffic into said section; a signal control relay for controlling said signals; a signal control lever in a distant office;

an indication relay in said ofiice; a pair of line wires extending from said ofilce to said signal; a source of current at said office and a source of current adjacent said signal; a control circuit for said signal control relay including said oifice source of current, a contact of said control lever closed only when said lever assumes an active position, a back contact of said indication relay and a front contact of said track relay; and a circuit for said indication relay including the source of current adjacent said signal, contacts of said control lever closed only when said lever assumes its inactive position and a back contact of each of said track relay and said signal control relay.

11. In combination With a central office and a distant-field station; a pair of line wires connecting said office and station; a source of current, two indication means and a control lever at said ofiice; a control relay and a control repeater relay at said field station; a track circuit including a track relay adjacent said control relay; a control circuit for said control relay including said source of current, one of said indication means, contacts of said lever closed only when said lever assumes an active position, said pair of line wires, and a front contact of said track relay; a first indication circuit including said contacts of said lever, said source of current, said one indication means, said pair of line wires, a back contact of said track relay and a front contact of said control relay; a second indication circuit including said contacts of said lever, said source of current,

said one indication means, said pair of line wires, a back contact of said track relay and a front stick contact of said control repeater relay; the impedance of said relays and said one indication means being such that said one indication means is renderedactive when included in either said first or said second indication circuit but is not rendered active when included in series in said control circuit; a third indication circuit including the other of said two indication means, contacts of said lever closed only when said lever assumes an inactive position, said pair of line wires, back contacts of said track relay and said control relay and a source of current at said field station; and a fourth indication circuit including said other indication means, a contact closed only when said other indication means is active, said pair of line wires, back contacts of said track relay and said control relay and said source of current at said field station.

12. In combination with a distant traflic controlling device and a local control lever for controlling the same; a track circuit including a track relay adjacent said traffic controlling device; a control relay for controlling said trafiic controlling device; a first indicator means and a second indicator means adjacent said lever for indicating the condition of occupancy of said track circuit; a line wire extending from a local point at which said lever is located to said distant point where said control relay is located; and two energizing circuits one including said line wire, a contact of said lever closed when said lever is in actuated position, a local source of current, said first indicator means, a front contact of said track relay and said control relay, and the other including said line wire, a contact closed when said lever assumes its normal position, said second indicator means, a back contact of said track relay, a back contact of said control relay and a source of current located at said distant point.

13. In combination with a distant trafiic controlling device and a local control lever for controlling the same; a track circuit including a track relay adjacent said trafiic controlling device; a control relay for controlling said trafiic controlling device; a first indicator means and a second indicator means adjacent said lever for indicating the condition of occupancy of said track circuit; a line wire extending from a local point at which said lever is located to said distant point where said control relay is located; a control repeater relay adjacent said control relay controlled through a front contact of said control relay; and two circuits one including said line wire, a source of current at said control lever, contacts of said control lever closed when said lever assumes its active position, the winding of said first indicator means and said control relay, and the other including said line wire, the winding of said second indicator means, a contact closed when said lever assumes an inactive position, a back contact of said control repeater relay, a back contact of said control relay and a source of current adjacent said control relay.

14. In combination, a local control lever, a distant traffic controlling means and a track relay associated therewith; a single line circuit connecting the local and distant locations; an indicating means adjacent said control lever; a control circuit for energizing said trafiic controlling means over said line circuit by movement of said lever from an inactive to an active position available only when said indication means is inactive and said track relay is energized and an indication circuit for energizing said indication means over said line circuit upon dropping of said track relay available only if said traflic controlling means is inactive and said control lever assumes its inactive position.

THOMAS J. JUDGE. 

